This
list should be followed in order to ensure for accurate adjustments.
Remember T-R-A-I-N...
• Tune guitar to concert pitch.
• Check and adjust neck Relief.
• Check and adjust the Action.
• Check and adjust the Intonation.
• Noodle away on your perfectly set-up Thorn
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Checking
neck Relief |
1. Tune guitar to concert pitch.
2. Relief should be checked with the guitar in the playing position.
2a. Capo all the strings on the first fret.
2b. Fret the high-E string on the 22nd fret with your right hand.
2c. Measure the distance between the 9th fret and the underside of the high-E. You can use
feeler gauges or a piece of guitar string. Thorns leave the shop with .012-.015 of relief.
If a B string can slide between there, and a G string cannot - the neck is within spec.
If a B sting (usually .011 - .013 in diameter) does not fit, then there is not enough
relief in the neck...the truss rod is too tight.
If a G string (usually .016 - .018 in diameter) fits underneath, then there is too much
relief in the neck...the truss rod is too loose.
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Adjusting
the Truss Rod |
3a. Remove the truss rod cover.
3b. Slacken the G and the D strings slightly. This will allow you to pop these strings out
of their nut slot and slide them out of the way for the wrench. Position the supplied
allen wrench into the end of the truss rod.
3c. Look at the end of the truss rod (or down the neck towards the body).
Rotating the wrench CCW will loosen the rod...adding more relief.
Rotating the wrench CW will tighten the rod...straightening the neck and reducing relief.
*** Do Not rotate the wrench more than a 1/8 turn without rechecking relief. Fine
adjustments are critical.
4. Reposition the G and D strings into the nut slots and retune to pitch. Check relief and
repeat steps 3b and 3c as needed.
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Checking
and Adjusting the Action |
5. Checking and adjusting the action should be done with the guitar in the playing
position. Thorns leave the shop with 1/16" (.062) action unless requested
differently. This measurement is taken between the 12th fret and the underside of each
string while the string is open ( not fretted ). You can use feeler gauges or an accurate
machinist's scale for measuring.
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Adjusting
the Action on a Thorn Tremolo Bridge |
5a. Adjusting the Action on a Thorn Tremolo. Each string has it's own saddle which can be
raised and lowered via two small set screws to adjust that string's height off the frets
(the Action). Use the supplied allen wrench and raise or lower each saddle until there is
a 1/16" (.062) between the 12th fret and the underside of each string.
Some players wish to have lower than a 1/16" Action, this is a personal preference
and can be adjusted to suit.
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Adjusting
the Action on a TonePros Wraparound equipped Thorn |
5b. Adjusting the Action on a TonePros Wraparound equipped Thorn. This bridge has two
locking studs which can be raised or lowered to universally adjust the Action. First
determine the current Action by placing the guitar in the playing position and measuring
the height under each string at the 12th fret (the strings must be unfretted).
If the distance is greater than 1/16" (.062), the action should be lowered.
5c. Loosen all the strings until they are slack.
5d. Loosen the "caps" of the locking studs on both ends of the bridge. You can
use the side of the TonePros wrench supplied.
5e. Underneath the bridge you will notice that the 2 studs protruding from the body have a
flange with a couple flats milled into them. The TonePros wrench fits these two flats for
rotating each stud. By turning the studs CW, the stud threads deeper into the body which
will lower the bridge...thus lowering the action. A 1/4 turn of each stud will lower the
overall action by approximately .005 of an inch. Note: Both studs do not need to be
adjusted.
5f. Once you have adjusted the stud(s), confirm that the bridge is firmly seated on them
and retighten the locking "caps".
5g. Retune to pitch and check the Action. Repeat steps 5c - 5g as needed.
If the action is less than 1/16" (.062), the action should be raised.
5h. Loosen all the strings until they are slack.
5i. Loosen the "caps" of the locking studs on both ends of the bridge. You can
use the side of the TonePros wrench supplied.
5j. Underneath the bridge you will notice that the 2 studs protruding from the body have a
flange with a couple flats milled into them. The TonePros wrench fits these two flats for
rotating each stud. By turning the studs CCW, the stud threads out of the body which will
raise the bridge...thus raising the action. A 1/4 turn of each stud will raise the overall
action by approximately .005 of an inch. Note: Both studs do not need to be adjusted.
5k. Once you have adjusted the stud(s), confirm that the bridge is firmly seated on them
and retighten the locking "caps".
5l. Retune to pitch and check the Action. Repeat steps 5h - 5k as needed.
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Adjusting
the Intonation |
6. Check and adjust the Intonation. An accurate tuner is preferred for this adjustment.
Intonation adjustment is usually necessary when new strings are fitted and as they
age.
Adjusting the intonation is performed by moving the individual string saddles forward or
backward as necessary to make the octaves in tune with the open string and the 12th fret
harmonic..
To check the intonation : Use an electronic tuner and tune the guitar to a standard
pitch.
Play the harmonic at the 12th fret, compare it to the fretted note at the 12th fret, these
notes should read the same on the tuner. Also compare the fretted note at the 12th
fret to the open string.Before adjusting the intonation, first determine the direction that the
saddle needs to be moved.
Note : If the 12th
fret is sharper than the open note, the saddle needs to be moved back.
If the 12th fret is flatter than the open note, the saddle needs to be moved forward.
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